The polyphenylene oxides and methods for their preparation are known in the art. Many types of catalysts have been employed in the preparation of these polymers including copper and manganese based catalysts. Manganese based catalysts for the oxidative coupling of phenolic monomers in the formation of polyphenylene oxides are disclosed in McNelis, U.S. Pat. No. 3,220,979; Nakashio, U.S. Pat. No. 3,573,257; Nakashio, U.S. Pat. No. 2,787,361 and Olander, U.S. Pat. No. 3,956,272. In the applicant's copending applications Ser. No. 491,475 filed July 24, 1974 and Ser. No. 534,903 filed Dec. 20, 1974, there are disclosed novel procedures for polymerizing polyphenylene oxides with complex manganese based catalysts. All of these patents and applications are hereby incorporated by reference.
The manganese complexes of the prior art are good catalysts for the oxidative coupling of phenolic monomers in the preparation of polyphenylene oxide resins. These catalysts however tend to be thermally unstable it is usually necessary to control the reaction temperature at a level that does not cause catalyst deactivation. It has now been found that a novel class of manganese based complexes derived from a manganese salt and an imine compound may be employed in the preparation of polyphenylene oxides under process temperatures that are higher than the temperatures usually employed with prior art manganese complexes.
The prior art complexes have included complexes that were prepared from manganese salts and an amine. In U.S. Pat. No. 3,787,361, a catalyst was prepared from an alkanolamine and manganese chloride. Other catalysts have been prepared from manganese salts and an imine that contains this groups and is derived from an unsaturated alkanolamine as described in Japanese patent publication No. 28680/74.
Accordingly, it is a primary object of this invention to provide a novel manganese catalyst for the oxidative coupling of phenolic monomers.
It is also an object of this invention to provide a manganese catalyst for the oxidative coupling of phenolic monomers which has improved thermal stability.